1. Field of the Invention
The present invention generally relates to an image sensor, and more particularly to a method of adaptively reducing power consumption in an image sensor.
2. Description of Related Art
An image sensor, such as a complementary metal-oxide-semiconductor (CMOS) image sensor, is a device that converts an optical image into electronic signals. The image sensor has been widely used in a variety of applications such as cell phones and cameras.
An image sensor is commonly equipped with an electronic rolling shutter, according to which the image sensor is reset row by row, and integrated charges are then read out row by row. A blanking period exists between readouts of two frames, during which a readout circuit is idle. It is thus proposed to turn off the readout circuit to save power. However, in normal light condition, the blanking period is usually too short such that the readout circuit ordinarily cannot recover from the turn-off state to become settled in time, therefore substantially affecting performance of the image sensor.
For the reason that conventional image sensors could not effectively save power, a need has thus arisen to propose a novel image sensor to overcome disadvantages of the conventional image sensors.